{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"c3c552757611bb602b39844df9be217d00345cc3b69b9ff07900792c71c85954","created":"2026-10-03T07:18:01Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"5722d4166816092012e08ba735f85bb61a5f75433f583c0dfeb9910ac08d9cd0","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"cm.spin-ice.dy2ti2o7-ground-state","kind":"well-posed","literature_status":"contested","n":"1","parents":[],"plain":"Ice-rule states are so numerous that spin ice keeps a leftover entropy at low temperature, as water ice does. Long-range dipolar forces predict an ordered state below about 0.2 K, but experiments struggle to reach equilibrium there.","posed_since":"2001","precise":"In Dy2Ti2O7, determine whether thermal equilibrium below 0.5 K approaches the ordered state predicted by the dipolar spin-ice model (transition near 0.18 K) with loss of the Pauling entropy $(R/2)\\ln(3/2)$ per mole Dy, or retains a disordered ice manifold. An answer is the equilibrium entropy and any ordering wavevector as $T \\to 0$.","problem_ref":null,"references":"","settled_by":"Equilibrium heat capacity and neutron scattering below 0.3 K after controlled long annealing, compared with Monte Carlo of the fitted dipolar model.","status_note":"Pomaranski et al. (Nature Physics 2013) found the residual entropy is lost after long equilibration without detecting the predicted order.","title":"Does classical spin ice Dy2Ti2O7 order or keep its Pauling entropy?","topic_ref":"52cddd9c3d75748e46e41f34a20edd20c81c928cc0056fa7e4de59ade0220e82"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"31a3a46024546948749390b73fc545a6b30dc5d0bfdeb81438cb4ac0924ce169","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"ef003ef910e91d91c748f729ee25deae8aa88729a890a87d31942375a5aaf3d7","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"c-miQknhGMF8KDX-ncI-bS-N4Wa8QC_UhmkYQzTIuzdLLPwFvgyZtYSBEUbv1EET0NcrklFHb57MP0_NUKh5Cw"},"schema":"pubphys.envelope/1"},"record_hash":"31a3a46024546948749390b73fc545a6b30dc5d0bfdeb81438cb4ac0924ce169","leaf_index":1169}